The US will deploy Patriot missile batteries and F-16 fighter jets in Jordan for military exercises, and the weapons may remain there indefinitely due to the threat of the Syrian civil war. The US has declined to comment on the size of the deployment.

The missile defense systems were "approved for deployment to
Jordan as part of Exercise Eager Lion," AFP quoted US Central
Command spokesperson Lt. Col. T.G. Taylor as saying. "In order
to enhance the defensive posture and capacity of Jordan, some of
these assets may remain beyond the exercise at the request of the
government of Jordan," he added.

The US has so far refused to reveal how many F-16s are being
deployed, or how many of them will remain in Jordan after the
exercises conclude. Jordanian officials have confirmed that the
missile defense systems are being sent, vowing they will only be
used to defend the country from potential missile attacks.

Jordan, an ally of Washington, shares a border with Syria and has
seen a huge influx of Syrian refugees displaced by the conflict.

Russia has condemned the US decision, arguing that the deployment
will only “pump more weapons into an already explosive
region,” Russian Foreign Ministry spokesperson Aleksandr
Lukashevich said. Lukashevich noted that that missile defense
system will be placed close to Syria, which is still embroiled in
a conflict that “Russia and the US are trying to resolve with
an international peace conference.”

The Patriot batteries are capable of shooting down Scud or other
short-range missiles – which are known to be part of the Syrian
military's arsenal – and could be used to enforce a no-fly-zone
over Syria.

NATO previously deployed Patriot batteries along the Turkey-Syria border, and
a contingent of 1,200 soldiers to operate them. The Syrian
government criticized the NATO deployment as a provocation, and
Russia and Iran have likewise protested the move.

Russia is often criticized for its commitment to ship S-300
missile batteries to Syria as part of a contract signed several
years ago. Moscow maintains that the deal does not violate
international law, and may help stem violence in the country.

The general director of MiG – the Russian arms manufacturer that
makes the jets of the same name – told Russian news agencies on
Friday that a Syrian delegation was in Moscow to discuss the
terms and deadline for a new contract to supply “more than
10” MiG-29 M/M2 fighters.

Washington’s decision could spark further worries about its
increasingly assertive role in the Syrian conflict.

The EU lifted an arms embargo on Syria at the end of May, allowing
European countries to “fully support” the rebels fighting
against the government of President Bashar Assad. Washington has
praised the development as giving Europe more flexibility to ramp
up pressure on Assad.

Moscow maintains that the Patriot deployment is both
counterproductive and potentially unlawful, since delivering arms
to non-governmental actors against the wishes of that country’s
government is a violation of international law. Such moves are
forbidden by both UN-level treaties on arms trade and the EU’s
own guidelines.

In a further development, the White House has reportedly asked
the Pentagon to outline plans for a military no-fly zone over Syria. A no-fly zone is
often enacted as a final precaution before military
intervention.

So far, the US has been reluctant to directly intervene in the
Syrian conflict, saying it was only a remote possibility. Still,
US lawmakers have on several occasions pushed for the US to adopt
a more aggressive stance.

Republican Senator John McCain (R-AZ), a staunch advocate for
supplying military aid to the Syrian opposition, made a surprise
visit to war-torn Syria at the end of May to
meet with the rebels.

The conflict in Syria has now entered its third year, with
Damascus the site of frequent bomb attacks. At least 80,000
people have been killed since the uprising against President
Assad began in March 2011, according to UN estimates.